Remove timeout from automation terminal util

I don't believe this was ever required, awaiting writeInTerminal should make sure the
data event is triggered in xterm, the following enter should just trigger another data
event. This doesn't guarantee it was accepted by the process yet, just that xterm.js
emitted the event.

Part of #137847

test/automation/src/terminal.ts

@@ -80,8 +80,6 @@ export class Terminal {
 
 	async runCommandInTerminal(commandText: string): Promise<void> {
 		await this.code.writeInTerminal(Selector.Xterm, commandText);
-		// hold your horses
-		await new Promise(c => setTimeout(c, 500));
 		await this.code.dispatchKeybinding('enter');
 	}